advertisement


Experience with DC Offset blocking devices, eg Isotek EVO 3 Synchro - anyone.?

Yanntoe

pfm Member
I think I've pretty much established that I have very noisy incoming mains and have to either reduce the hum through the amp casing and speakers or sell everything a get some Sonos!(if it doesn't hum).

Drastic I know, but the hum is really intrusive when music is not playing so it either has to go or I should start again with things that don't hum. Won't sound as good but it'll be livable with!

So anyone cured mains hum with add on boxes - isolation transformers , DC offset blockers, combinations of various things or ...........

I guess it's a specific question which relates purely to hum, at this point that's the key focus, not that interested in improving the sound in other areas as if the hum stays, the system will be probably find it's way into the classifieds or onto e-bay soon.

So anyone have any experience in resolving this problem using "more boxes"?
 
How are your DIY skills? https://www.pinkfishmedia.net/forum/threads/dc-blocker-gb-closing-soon.216403/

Just received mine this morning Per, https://www.pinkfishmedia.net/forum/threads/dc-blockers.235780/page-5

I can vouch for this DC Blocker. It really works, the design and board quality are first class.
With the DC removed the noise floor has dropped considerably and the transients are better etched in space.

Raj

You can buy them direct from his website. I did and it arrived in 5 days. Took me 60 mins to build it using 60/40 solder. It's really simple, just make sure you have +60w iron
https://sjostromaudio.net/cart/gb/

 
No way I can build a filter with my sight so I have been using an Isotek Syndro (the initial version with a can on the mains lead) to control DC offset for some time. It does the job.
 
had 3 syncro , beautiful bit of kit . plugged my puresound L10 into it and really improved its sense of musicality , only sold them because i had to pay the bills . they are a bit expensive but recently one was up for under 500
 
I think I've pretty much established that I have very noisy incoming mains and have to either reduce the hum through the amp casing and speakers or sell everything a get some Sonos!(if it doesn't hum).

Drastic I know, but the hum is really intrusive when music is not playing so it either has to go or I should start again with things that don't hum. Won't sound as good but it'll be livable with!

So anyone cured mains hum with add on boxes - isolation transformers , DC offset blockers, combinations of various things or ...........

I guess it's a specific question which relates purely to hum, at this point that's the key focus, not that interested in improving the sound in other areas as if the hum stays, the system will be probably find it's way into the classifieds or onto e-bay soon.

So anyone have any experience in resolving this problem using "more boxes"?
Yes I did once. I had a Sonos ZP90 into my then 47 Labs amps and had to unplug the Sonos if I wanted to listen to vinyl as the interference through the mains made it unusable. The addition of a Russ Andrews Zapperator helped but an old old DPA Audio The Power (a filter, I believe) sitting between the mains socket and the Sonos power in fixed it. It drove me nuts for a while as everytime I wanted to stream something, I had to wait for the Sonos box to start up and get an IP address etc.
 
The 557 has a massive 1200va transformer, I’d be very surprised if the Little DC blocker does anything or doesn’t manage to strangle it’s dynamics!
 
The 557 has a massive 1200va transformer, I’d be very surprised if the Little DC blocker does anything or doesn’t manage to strangle it’s dynamics!

That would give it a peak current draw of 1200 watts. That's 5 amps at 240V AC. It isn't going to bother the "little" DC blocker. I suggest you do a little bit more reading on the subject. These things aren't designed to "improve the sound" or any such nonsense, they're designed to stop the irritating buzz of larger transformers caused by DC on the mains.
 
OK then, just trying to give you some actual real world experience.

Try having a look at the max current and associated peaks.

Even Alex (the guy who owns ATL) recommends the smaller blockers for up to 500va. Try emailing him, he’s a very informative chap (and also a PFM member).
 
Thanks everyone.

Just to confirm.....
The suggestions above, i.e. the Isotek Synchro 3, the ATL DC blockers, the Power Inspired AG1500, the airlink transformer (one of) might help with both aspects - i.e. mechanical hum and corresponding/related hum through the speakers?

If so I'll check these out some more. The Airlink stuff seems very practical so I might contact them in the first instance.

Checked the incoming mains and it comes in at AC 252V, so it's fairly pokey!

Thanks for all the suggestions and if anyone has experience of reducing hum with these types of devices do chip in

Oh, and Cereal Killer, much as I'd like to have a go at the DIY stuff, and whilst I'm OK at soldering and repairing guitar electrics etc, I'm not sure I'm brave enough to actually plug anything I make into the full 252 Volts - it's a kind of Pavlovian terror - waiting for that electrical "crack" and the corresponding smell of melting components. I might have a go once I've really finished everything on the house, but that's probably a year or so away!
 
If you were happy to order all the DCT03 bits i'd be happy to build and soak test it before sending it too you, then all you'd need to do is put it in a box/case etc. It really works, and for c£80 also highly cost effective.
 
I'm with CK here, anything above 500va use the bigger dct03, the small ones dont cut it. Based on having built and used a number of smaller blockers with various bits of kit.

You can of course choose to ignore the advice of those who've built multiple dc blocker modules and buy what you 'think will work.
 


advertisement


Back
Top